<![CDATA[Background: In the South Sumatra Provincial Health Office surveillance data, disease severity was operationally identified based on the presence of apnea, which was the available clinical indicator of severe disease. This study aims to analyze factors associated with disease severity among patients with pertussis in South Sumatra Province.Methods: This analytical retrospective cross-sectional study used surveillance data from the South Sumatra Provincial Health Office collected from 2022–2024. Using total sampling, 197 laboratory-confirmed pertussis cases that met the inclusion criteria were included, while cases with incomplete data were excluded. Severe pertussis was defined based on the presence of apnea. Data were analyzed using univariate, bivariate (chi-square test), and multivariable analyses (multiple logistic regression) to estimate ORs with 95% CIs.Result: Among the 197 laboratory-confirmed pertussis cases, 21.2% had severe pertussis. Most patients were aged ≤ 4 months (49.7%) and female (55.3%). Bivariat analysis using the chi-square test showed a significant relationship between age PR 2,02 (95%CI 1,13 - 3,60), p-value 0,022; immunization status PR 3,97 (95%CI 1,12 - 14,7), p-value 0,032; and antibiotic administration PR 1,93 (95%CI 1,12 – 3,35), p-value 0,025 with severe pertussis. The result of multivariate analysis showed that variable of immunization completeness OR 5,45 (95%CI 1,21 – 24,4), p-value 0,027 was the most dominant variable in influencing disease severity.Conclusion : Strengthening age-appropriate DPT immunization programs and improving parental education on the importance of complete and timely DPT immunization are recommended.]]>
